干旱区生态环境知识资源中心

Galls produced by the cecidomyiid Lasioptera ephedricola on Ephedra trifurca always have a black ring associated with them while galls produced by the congener L. ephedrae never do. Black ring material, after microscopic examination and culture proved to be Aureobasidium pullulans. In addition to lacking black ring material. neither L. ephedrae galls nor healthy stems consistently yielded Aureobasidium on culture. Gall and larva size measurements indicated that continued larval presence is not necessary for gall development, suggesting fungus initiated gall formation. However, inoculation of healthy stems with Aureobasidium caused lesions but not galls. The mycelium in galls did not appear grazed and neither larvae nor pupae contained Aureobasidium propagules suggesting that larvae do not feed directly on fungi. These data also suggest that there is no trans-pupal passage of fungus from larvae or pupae to adults. Newly emerged females do not carry fungal propagules suggesting that they are not inoculated upon exiting the gall. Gall position, leaf culture and stem culture data suggest that the fungus is picked up from leaves prior to oviposition.